Apparatuses and methods for compute enabled cache

ABSTRACT

The present disclosure includes apparatuses and methods for compute enabled cache. An example apparatus comprises a compute component, a memory and a controller coupled to the memory. The controller configured to operate on a block select and a subrow select as metadata to a cache line to control placement of the cache line in the memory to allow for a compute enabled cache.

PRIORITY INFORMATION

This application is a Continuation of U.S. application Ser. No.16/126,169, filed Sep. 10, 2018, which issues as U.S. Pat. No.10,372,612 on Aug. 6, 2019, which is a Continuation of U.S. applicationSer. No. 15/066,488, filed Mar. 10, 2016, which issued as U.S. Pat. No.10,073,786 on Sep. 11, 2018, which claims the benefit of U.S.Provisional Application No. 62/167,451, filed May 28, 2015, the contentsof which are included herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to semiconductor memory andmethods, and more particularly, to apparatuses and methods for computeenabled cache.

BACKGROUND

Memory devices are typically provided as internal, semiconductor,integrated circuits in computing systems. There are many different typesof memory including volatile and non-volatile memory. Volatile memorycan require power to maintain its data (e.g., host data, error data,etc.) and includes random access memory (RAM), dynamic random accessmemory (DRAM), static random access memory (SRAM), synchronous dynamicrandom access memory (SDRAM), and thyristor random access memory (TRAM),among others. Non-volatile memory can provide persistent data byretaining stored data when not powered and can include NAND flashmemory, NOR flash memory, and resistance variable memory such as phasechange random access memory (PCRAM), resistive random access memory(RRAM), and magnetoresistive random access memory (MRAM), such as spintorque transfer random access memory (STT RAM), among others.

Computing systems often include a number of processing resources (e.g.,one or more processors), which may retrieve and execute instructions andstore the results of the executed instructions to a suitable location. Aprocessing resource (e.g., CPU) can comprise a number of functionalunits such as arithmetic logic unit (ALU) circuitry, floating point unit(FPU) circuitry, and/or a combinatorial logic block, for example, whichcan be used to execute instructions by performing logical operationssuch as AND, OR, NOT, NAND, NOR, and XOR, and invert (e.g., inversion)logical operations on data (e.g., one or more operands). For example,functional unit circuitry may be used to perform arithmetic operationssuch as addition, subtraction, multiplication, and/or division onoperands via a number of logical operations.

A number of components in a computing system may be involved inproviding instructions to the functional unit circuitry for execution.The instructions may be executed, for instance, by a processing resourcesuch as a controller and/or host processor. Data (e.g., the operands onwhich the instructions will be executed) may be stored in a memory arraythat is accessible by the functional unit circuitry. The instructionsand/or data may be retrieved from the memory array and sequenced and/orbuffered before the functional unit circuitry begins to executeinstructions on the data. Furthermore, as different types of operationsmay be executed in one or multiple clock cycles through the functionalunit circuitry, intermediate results of the instructions and/or data mayalso be sequenced and/or buffered.

In many instances, the processing resources (e.g., processor and/orassociated functional unit circuitry) may be external to the memoryarray, and data is accessed via a bus between the processing resourcesand the memory array to execute a set of instructions. Processingperformance may be improved in a processing-in-memory (PIM) device, inwhich a processor may be implemented internal and/or near to a memory(e.g., directly on a same chip as the memory array). Aprocessing-in-memory (PIM) device may save time by reducing and/oreliminating external communications and may also conserve power.

A typical cache architecture (fully associative, set associative, ordirect mapped) uses part of an address generated by a processingresource to locate the placement of a block in the cache and may havesome metadata (e.g., valid and dirty bits) describing the state of thecache block. A last level cache architecture may be based on 3Dintegrated memory, with tags and metadata being stored on-chip in SRAMand the block data in quickly accessed DRAM. In such an architecture,the matching occurs using the on-chip SRAM tags and the memory access isaccelerated by the relatively fast on-package DRAM (as compared to anoff-package solution).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram of an apparatus in the form of a computingsystem including a memory device in accordance with a number ofembodiments of the present disclosure.

FIG. 1B is a block diagram illustrating the use of a cache line having ablock select and subrow select for storage and/or retrieval of cacheblocks in an array.

FIG. 1C is a block diagram illustrating that the block select and subrowselect structure to a cache line can be repeated to allow a cache lineto be split and placed differently within a cache block, array, and/ormemory device.

FIG. 1D is another block diagram of an apparatus in the form of acomputing system including a memory device in accordance with a numberof embodiments of the present disclosure.

FIG. 1E is a block diagram of a bank to a memory device in accordancewith a number of embodiments of the present disclosure.

FIG. 1F is another block diagram of a bank to a memory device inaccordance with a number of embodiments of the present disclosure.

FIG. 2 is a schematic diagram illustrating sensing circuitry to a memorydevice in accordance with a number of embodiments of the presentdisclosure.

FIG. 3 is a schematic diagram illustrating sensing circuitry to a memorydevice in accordance with a number of embodiments of the presentdisclosure.

FIG. 4 is a logic table illustrating selectable logic operation resultsimplemented by a sensing circuitry shown in FIG. 3 in accordance with anumber of embodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure includes apparatuses and methods for computeenabled cache, e.g., as may be implemented for processing-in-memory(PIM) and/or 3D cache integrated memory. In one example embodiment, anapparatus is provided having a compute component, a cache memory and acache controller coupled to the cache memory. The cache controller isconfigured to create a block select as metadata to a cache line and tocreate a subrow select as metadata to the cache line to provide acompute enabled cache. An interface is coupled between the cache memoryand the compute component. In one example embodiment the interfaceincludes through silicon vias (TSVs) connecting a plurality of memorydie to a logic die as part of a three dimension (3D) integrated memory.As used herein, TSVs may be entirely or partially through vias andinclude substrate materials other than silicon.

In another example embodiment, the apparatus comprises a memory devicecoupled to a host. The memory device may be coupled to the host via abus such as a data bus and/or a control bus. The memory device includesan array of memory cells and sensing circuitry coupled to the array. Inone example, the array may be coupled to the sensing circuitry via aplurality of sense lines. The sensing circuitry includes a senseamplifier and a compute component configured to implement logicaloperations.

A controller, e.g., memory controller, is coupled to the array andsensing circuitry. The controller is configured to receive a cache linehaving block select and subrow select metadata to allow the memorydevice to operate as a compute enabled cache. The controller is furtherconfigured to operate on the block select and subrow select metadata tocontrol alignment of cache blocks in the array and to allow a cacheblock to be placed on multiple different rows to the array. In oneembodiment, the controller is configured to store cache blocks in thearray and to retrieve cache blocks to perform logical operations withthe compute component.

According to some embodiments, the cache architecture described above(e.g., for fully associative, set associative, or direct mapped) may usepart of an address generated by a processing resource to locate theplacement of a block of data in cache memory. In previous approachesthis address may have included metadata such as valid and dirty bits fordescribing a state of the cache block, but the address does not containany metadata or tags for placement of the cache block in differentalignments or in multiple different locations in a manner transparent tothe host processor in order to facilitate or to provide a computeenabled cache. In particular the cache lines are not constructed in amanner which can leverage the compute capability of a processor inmemory (PIM) device.

The improvements described herein overcome such hurdles by providing acache controller which is configured to create a block select asmetadata to a cache line and to create a subrow select as metadata tothe cache line.

In the following detailed description of the present disclosure,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration how one or more embodimentsof the disclosure may be practiced. These embodiments are described insufficient detail to enable those of ordinary skill in the art topractice the embodiments of this disclosure, and it is to be understoodthat other embodiments may be utilized and that process, electrical,and/or structural changes may be made without departing from the scopeof the present disclosure. As used herein, designators such as “N”, “M”,etc., particularly with respect to reference numerals in the drawings,indicate that a number of the particular feature so designated can beincluded. As used herein, “a number of” a particular thing can refer toone or more of such things (e.g., a number of memory arrays can refer toone or more memory arrays). A “plurality of” is intended to refer tomore than one of such things.

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits. For example, 206 may referenceelement “06” in FIG. 2, and a similar element may be referenced as 306in FIG. 3. As will be appreciated, elements shown in the variousembodiments herein can be added, exchanged, and/or eliminated so as toprovide a number of additional embodiments of the present disclosure. Inaddition, as will be appreciated, the proportion and the relative scaleof the elements provided in the figures are intended to illustratecertain embodiments of the present invention, and should not be taken ina limiting sense.

FIG. 1A is a block diagram of an apparatus in the form of a computingsystem including a memory device in accordance with a number ofembodiments of the present disclosure. As shown in FIG. 1A a host 110can include a processing resource, such as logic resource 112. As usedherein, a logic resource (also referred to sometimes as “logic layer” orjust “logic”) is intended to mean firmware (e.g., in the form ofmicrocode instructions) and/or hardware such as transistor circuitryand/or one or more application specific integrated circuits (ASICs). Inat least one embodiment the logic resource 112 can include a staticrandom access memory (SRAM) memory on the logic resource 112. As shownin the example embodiment of FIG. 1A, the logic resource 112 can becoupled on the host 110 to a cache memory 113 on the host 110, e.g.,on-package (also referred to as on-chip and/or on-die) such as in a 3Dintegrated memory. The logic resource 112 can be coupled to the cachememory 113 via a wide, e.g., 256 bit interface, interface 114. Thisinterface may include through silicon vias (TSVs) as part of a 3Dintegrated memory having multiple memory die stacked on a logic die.

In one or more embodiments the cache memory 113, shown associated withthe host in FIG. 1A, can have a replica in the form of a plurality ofarrays, memory layers, banks, bank sections, subarrays, rows, etc., on amemory device 120 in a number of allocated locations in an array 130 ofthe memory device 120. Alternatively, all or at least a portion ofmemory device 120 may be substituted as cache memory 113 on package withthe logic resource 112 on the host 110. Embodiments are not so limited.In at least one embodiment, a portion of the cache memory 113, and/orthe number of allocated locations in the array 130, may serve as a lastlayer cache (LLC) portion. According to embodiments, an LLC havingand/or able to operate on subrow select and block select metadata, asdescribed further below, can control block data alignment and may reducean overall data size of cache memory, whether in a 3D integrated memorychip or in a separate processing in memory random access memory (PIMRAM)device, e.g., memory device 120.

As shown in FIG. 1A a cache controller 115 may use firmware (e.g.,microcode instructions) and/or hardware, e.g., an application specificintegrated circuit (ASIC). According to embodiments, firmware and/orhardware used by the cache controller 115 is configured to create ablock select as metadata to a cache line and to create a subrow selectas metadata to the cache line (shown in more detail in FIG. 1B). In oneembodiment the block select enables an offset to the cache line and thesubrow select enables multiple sets to a set associative cache. In oneembodiment the block select provides an offset to a page in a dynamicrandom access memory (DRAM).

The cache controller 115 can provide cache lines having the block selectand the subrow select metadata to the number of allocated locations inarray 130 of memory device 120 to provide a compute enabled cache onmemory device 120. Alternatively, in a 3D integrated memory chipexample, memory banks may have independent TSV paths, e.g., interface114 on host 110, into them and may be controlled explicitly by the cachecontroller 115. Cache blocks having subrow select metadata and blockselect metadata, as illustrated and described more in FIG. 1B, can bemoved from an SRAM in the logic resource 112 into cache memory in DRAM,e.g., as part of a 3D integrated cache memory 113 on host 110 or to anumber of allocated locations in array 130 on a PIMRAM 120. In variousexample embodiments, the placement of the cache blocks will becontrolled using the subrow select and block select metadata datastructures created by the cache controller 115 and added to cache lines.

As used herein, a “cache block” is intended to mean an addressable areain memory that is being used in a cache memory function. An addressablecache block may include one or more addressable cache lines. Hence, anaddressable cache line may have a bit length that is equivalent to anaddressable bit width of a cache block, but a cache block may includemore than one addressable cache line. Additionally, a cache block mayhave an addressable bit width that is less than an addressable bitlength of the cache line, such as an addressable “chunk” within thecache block as described in more detail below.

For example, according to a particular cache architecture on a givendevice a cache line may be configured to have a bit length of 128 bytes.An addressable cache block on the particular device or on anotherdevice, e.g., memory device 120, may also have an addressable bit widthof 128 bytes. As described in further detail below, block selectmetadata data structures according to various embodiments are providedthat enable a selection of all and/or a portion of that 128 byte bitlength to the cache line, e.g., the entire 128 bytes and/or a portion ofhaving a smaller bit length (referred to herein as a “chunk”) of just256 bits, 64 bits, etc. Embodiments are not so limited.

In at least one embodiment, the block select and subrow select metadatadata structures, created by the cache controller 115, are datastructures used internal to the compute enabled cache, e.g., stored andmaintained between the cache controller 115 and cache memory 113 on thehost or between the number of allocated locations in array 130 and acontroller 140 on the PIMRAM 120. For example, the subrow select andblock select metadata data structures do not have to be stored,maintained or tracked as part of an address to the logic resource 112 onthe host 110. In this manner, the cache controller 115 and/or controller140 on the memory device 120 is configured, by firmware and/or hardwareexecuting instructions and/or performing logic operations, to be able tochange the block select and the subrow select and to relocate the cacheblock data transparently to the logic resource 112 on the host 110. Inother embodiments, however, the cache controller 115 can additionally beconfigured to store and maintain a copy of the block select and subrowselect metadata structures with the logic resource 112 on the host 110.

FIG. 1B is a block diagram illustrating the use of a cache line having ablock select and subrow select for storage and/or retrieval of cacheblocks in an array. As shown in the example illustration of FIG. 1B, thecache controller 115 and/or controller 140 described in FIG. 1A may beconfigured, by firmware, and/or hardware executing instructions and/orperforming logic operations, to create a block select 162 and row select163 data structure to insert in a cache line 160.

As shown in FIG. 1B, an address 161 including a tag and an offset may beprovided according to a cache memory architecture of a host 110 or otherdevice, e.g., memory device 120. The received address may be compared toa cache line 160, e.g., compared to direct mapped tags, for one or morematches 165 indicating a location in cache memory, generally shown byarrow 171, to locate the cache line. However, according to embodimentsdescribed herein, a controller, e.g., cache controller 115 and/orcontroller 140, can insert additional block select 162 and row select163 metadata data structures into the cache line 160 which may be usedto specify a particular cache block, 127-0, . . . , 127-N, shown byarrow 167, and/or a particular row, shown by arrow 169, in relation tothe particular cache block. For example, a particular cache block, e.g.,block 127-5, may be selected using the block select metadata 162.Further a particular row, e.g., row 126-0, row 126-1, etc., may beselected using the row select metadata 163 in order to align aparticular bit vector, chunk, and/or cache line data to a particularcompute component, e.g., 150-5, in sensing circuitry 150 of anarray/sensing circuitry alignment 130/150, e.g., according to aparticular digit line/compute component alignment as described in moredetail in connection with FIGS. 2 and 3.

As mentioned, the block select metadata data structure 162 may providean offset to the cache line and function as an offset to a page in DRAM.As such the block select metadata 162 may be used to control alignmentof cache blocks within an array in the cache memory 113 on the host 110(shown in FIG. 1A) or may be used by controller 140 to control alignmentof cache blocks within array 130 in the memory device 120. The subrowselect metadata 163 may enable multiple sets in a set associative cacheand may control placement of a cache block such that a replicated and/orsplit cache line and/or cache block may be placed on multiple differentrows in an array in the cache memory 113 on host or array 130 on thememory device 120.

As used herein, set associative cache refers to combination of directmapped cache (e.g., in which each block is mapped to exactly onelocation) and fully associative cache (e.g., which is similar to directcache mapping but allows a cache block to be mapped to any cachelocation). In set associative cache, each cache block is mapped to asubset of cache locations. Thus, according to embodiments, the term“multiple sets” is intended to mean that the subrow select metadata mayallow for a cache line and/or cache block to be split and/or replicatedsuch that the split cache line and/or split block can be placed inmultiple different subsets of cache locations in order to achieved aparticular alignment. For example, the subrow select metadata datastructure 163 allows for a given cache line to be placed on multipledifferent rows. As shown in FIG. 1B the subrow select metadata datastructure 163 can be added as a portion of a tag. As used herein, a“tag” to a cache line is intended to mean a unique identifier for agroup of data in the cache. Metadata, as used herein, is intended tomean one or more additional bits that serve as additional informationabout the data to which it is associated, e.g., data describing otherdata.

FIG. 1B illustrates an example 1K (one Kilobit) cache line 160 includingmetadata and tags along with cache block data. According to embodimentsdescribed herein, the additional block select metadata 162 and thesubrow select metadata 163, e.g., as may be created by the cachecontroller 115, are inserted (as shown by “arrow”) into the cache line160. The block select metadata data structure 162 and subrow selectmetadata data structure 163 advantageously contribute to providing acompute enabled cache on a host 110 and/or on a memory device 120 inseveral ways.

For example, in a typical cache architecture, or even with 3D integratedmemory, a DRAM will access significantly more data than requested. Forexample, with a 3D integrated memory having TSVs, a cache request of 256bits may cause a DRAM to access up to 16K+ columns (16,000+ bits). Ifthis 256 cache request were to a cache memory system having a bit widthof only 128 bytes, then the cache request of 256 bits would only usepower and signaling time to access a row having a bit width of 128bytes. To cause a DRAM to access a full 16K+ columns (16K+ bits) may besignificantly more costly in use of power and signaling time thanaccessing a row having a bit width of only 128 bytes in a 128 byte cachememory architecture.

Thus, according to embodiments of the present disclosure, a block selectmetadata data structure 162 can selectively control which part of thatsame 16+ Kbit wide row of bits to access, e.g., shown by match selection“arrow” 167. In this example, arrow 167 illustrates the block selectmetadata 162 being used to select a particular cache block 127-0, . . ., 127-N, in an array 121 of cache memory (e.g., in cache memory 113 onhost 110 or in a number of locations in an array 130 on memory device120 in FIG. 1A) to access. By way of example, and not by way oflimitation, a cache controller 115, logic resource 112, controller 140(below), or other compute component (e.g., sensing circuitry describedbelow) may access the metadata data structures (e.g., block select 162and subrow select 163) described herein and operate to compareinformation therein, e.g., bits (flags), or other value in a multiplebit scenario, to a reference bit or bit value to determine a logicalaction or subsequent action.

In FIG. 1B, the array in cache memory 121 can be a DRAM bank that is 16k columns wide. There may be a plurality of bank sections 123 within aDRAM bank to the array 121 and each bank section 123 may have aparticular number of rows, e.g., a bank section 123 may have 512 rows.By way of illustration, and not by way of limitation, FIG. 1B shows aplurality of blocks 127-0, . . . , 127-N across a 16K+column wide banksection 123. A block 127-0, . . . , 127-N in the bank section may have a1K+ column width, e.g., a width configured to be substantiallyequivalent in bit length to a 1K+ bit length cache line, e.g., cacheline 160. Hence, the block select metadata 162 can be used by a cachecontroller 115 and/or a controller 140 in a PIM capable device to selectwhich part of an entire 16K+ bit wide row of bits to access, equivalentto a cache line bit length. For example, according to variousembodiments, the block select metadata 162 may be used to select of alland/or a portion of a 128 byte bit length cache line, e.g., the entire128 bytes and/or a portion of having a smaller bit length.

In one example, the block select metadata 162 may be used to select asmaller bit length, e.g., a 256 bit chunk. The purpose for selecting thesmaller bit length, e.g., equating to a 256 bit chunk, may be to match abit width to a particular interface, for example a 256 bit interface(114 in FIG. 1A) to a 16K+ column memory array. This may, for example,provide even further granularity to a 16K+ column wide DRAM row access.In this example, the block select metadata 162 may be six (6) bits wideto select a 256 bit chunk. In a further example, the block selectmetadata 162 data structure may be eight (8) bits wide to providefurther granularity and to access a 64 bit value within a 256 bit chunk.As used herein, the term “chunk” is intended to refer to a smaller bitlength portion of a cache block depending on a particular designimplementation. For example, a cache block may have a bit length of 128bytes and a “chunk in a particular design implementation may have asmaller, defined bit length, e.g., 256 bits, 64 bits, etc.

As will be evident further below in this disclosure, such granularselection capability can be of great assistance to a processing inmemory (PIM) based memory device in which vectors need to be aligned toperform processing. In one example, each cache line can be handled ashaving one or more vectors and a vector may have a plurality of elementshaving multiple bits representing numerical values. For example a vectormay have four (4) 64 bit values, e.g., numerical values. Each 64 bitvalue can be an element to a vector in a logical operation. The vectoror the individual elements may be handled as a “chunk” as describedherein. Block select metadata 162 may be used to control the alignmentof such a “chunk”, e.g., vector and/or the elements to a vector, in anarray, subarray, etc.

Further, the additional subrow select metadata data structure 163, e.g.,as created by the cache controller 115, may be inserted (as shown by“arrow”) into the cache line 160 and used to select which row, e.g.,which row in a subarray, to access. As shown in FIG. 1B, the subrowselect metadata structure 163 can be added to a portion of the tags inthe cache line 160. For example, a four (4) bit subrow select datastructure 163 will allow a selection of one (1) of sixteen (16) rows ina DRAM array, e.g., within a 16 row subarray, for a given cache block127-0, . . . , 127-N. These rows would have to be allocated and free forthe cache memory (e.g., cache 113 on host or the number of allocatedlocations in array 130 on memory device 120 in FIG. 1A) to access. Thesubrow select metadata 163 is thus shown in the example of FIG. 1B beingused to select, e.g., at arrow 169, a row in a subarray 125. The subrowselect metadata 163 could also be used to select which subarray aparticular element is placed in as a resource allocation.

FIG. 1C is a block diagram illustrating that the block select and subrowselect data structures to a cache line can be used to separate a cacheline 160 into chunks 190. As described above, a chunk may have a smallerbit length than that of an entire cache line or cache block width in aDRAM array, e.g., blocks 127-0, . . . , 127-N shown in FIG. 1B. Thedifferent selected bit width to a chunk may depend on a particulardesign implementation. In one embodiment a chunk is chosen to have a bitwidth of 256 bits to match a width of a particular interface bandwidth,e.g., interface 114 in FIG. 1A, also having a bit width of 256 bits. Inthis example, shown in FIG. 1C, there would be four (4) chunks (e.g.,Chunk 0, . . . , Chunk N) 190 in a 1K+ bit wide cache line 160. As shownin FIG. 1C and discussed above, the block select (BS) metadata datastructure 162 may be used as an offset to the cache line 160 to select aparticular chunk, e.g., Chunk 0, in a given cache line 160.

Additionally, the subrow select (SRS) metadata data structure 163 may beused to allow for a given cache line 160 to be placed on multipledifferent rows in a cache block, e.g., cache block 127-0, . . . , 127-N,in an array, bank, bank section, subarray, etc., as shown in FIG. 1B.Thus, the example embodiment of FIG. 1C illustrates that the blockselect metadata data structure 162 and the subrow select metadata datastructure 163 can be repeated to allow a cache line to be split andplaced differently within a cache block, array, and/or memory device.The subrow select metadata data structure 163 allows for multipleplacements vertically and enables joining data items that may need to becombined, e.g., in a PIM based device. Hence, according to embodiments,addition the two additional metadata data structures, block select andsubrow select, can control the alignment (block select) and resourceallocation (subrow select) to provide a compute enabled cache.

The advantages described above can be leveraged even further in a PIMbased device. In particular, the additional capability of blockalignment and resource allocation can be leveraged in a PIM baseddynamic random access memory (PIMRAM). For example, the embodimentsdescribed herein can additionally be employed in a PIMRAM to provide acompute enabled cache capability on the PIMRAM.

To illustrate, FIG. 1A additionally shows the coupling of a host 110 toa memory device 120. A cache line with block select 162 and subrowselect metadata data structures can be stored in quickly accessibledynamic random access memory (DRAM) and operated by the controller 140and/or sensing circuitry 150 to a PIMRAM. This then affords an efficientmethod of providing a large number of instructions, with arguments, tothe DRAM and then route those instructions to an embedded processingengine, e.g., controller 140 and/or sensing circuitry 150, of the DRAMwith low latency, while preserving the protocol, logical, and electricalinterfaces for the DRAM. Hence, embodiments described herein mayfacilitate keeping the A/C bus at a standard width and data rate,reducing any amount of “special” design for the PIMRAM and also makingthe PIMRAM more compatible with existing memory interfaces in a varietyof computing devices.

Previous approaches such as 3D integrated memory may have included anon-chip SRAM, but did not afford the opportunity to align elements for acompute component to sensing circuitry 150 as required for processingbit vectors in a PIMRAM. According to various embodiments PIM operationscan involve bit vector based operations. As used herein, the term “bitvector” is intended to mean a physically contiguous number of bits on abit vector operation capable memory device, e.g., PIM device, whetherphysically contiguous in rows (e.g., horizontally oriented) or columns(e.g., vertically oriented) in an array of memory cells. Thus, as usedherein a “bit vector operation” is intended to mean an operation that isperformed on a bit-vector that is a contiguous portion (also referred toas “chunk”) of virtual address space, e.g., used by a PIM device. Forexample, a chunk of virtual address space may have a bit length of 256bits. A chunk may or may not be contiguous physically to other chunks inthe virtual address space.

For example, in a logical division operation in a PIMRAM, bit vectorscomprising variable bit-length vectors may be divided. This can includedividing a first vector with variable length elements by a second vectorwith variable length elements. The first vector can represent a numberof dividends and be stored in a group of memory cells coupled to a firstaccess line and a number of sense lines in an array. The second vectorcan represent a number of divisors and be stored in a group of memorycells coupled to a second access line and the number of sense lines inthe array. The division operation can include a number of ANDoperations, OR operations, SHIFT operations, and INVERT operationsperformed without transferring data via an input/output (I/O) line. Inthis example, a first element and a second element can be numericalvalues that are divided by each other. Elements to be divided can bereferred to as operands of a division operation. The elements can benumerical values that can be stored in memory as bit-vectors andretrieved to and stored in a last layer cache (LLC), DRAM equivalent inthe PIMRAM to be operated upon according to embodiments of the presentdisclosure.

As described in more detail below, the embodiments can allow a hostsystem to allocate a number of locations, e.g., sub-arrays (or“subarrays”) or portions of subarrays in a plurality of DRAM banks tocache blocks. The host system and/or the PIMRAM may perform the addressresolution for a cache line on an entire cache block, including theaddition of the block select metadata data structures 162 and the subrowselect metadata data structures 163. The cache lines 160 and cacheblocks 127-0, . . . , 127-N may then be written into the allocatedinstruction locations, e.g., subarrays, within a target bank. Commandmay utilize the normal DRAM write path to the DRAM device. After thecache lines and cache blocks are written into the storage locations,e.g., subarrays, a DRAM bank controller, e.g., memory controller, mayretrieve and operate on the cache lines 160 and cache blocks 127-0, . .. , 127-N in an equivalent manner to a last layer cache's (LLCs)operation on a host, e.g., 110 in FIG. 1A. The memory controller willpull cache block data from the storage subarrays as necessary to handlethe branches, loops, logical and data operations contained with theinstruction block, caching the instructions and refilling the LLC cacheas necessary. As the reader will appreciate, while a DRAM style PIMdevice is discussed with examples herein, embodiments are not limited toa DRAM processor-in-memory (PIM) implementation.

In order to appreciate the improved program instruction techniques anapparatus for implementing such techniques, a discussion of a memorydevice having PIM capabilities, and associated host, follows. Accordingto various embodiments, program instructions, e.g., PIM commands,involving a memory device having PIM capabilities can distributeimplementation of the PIM commands over multiple sensing circuitriesthat can implement logical operations and can store the PIM commandswithin the memory array, e.g., without having to transfer them back andforth with a host over an A/C bus for the memory device. Thus, PIMcommands involving a memory device having PIM capabilities can becompleted in less time and using less power. Some time and poweradvantage can be realized by reducing the amount of data that is movedaround a computing system to process the requested memory arrayoperations (e.g., reads, writes, etc.).

A number of embodiments of the present disclosure can provide improvedparallelism and/or reduced power consumption in association withperforming compute functions as compared to previous systems such asprevious PIM systems and systems having an external processor (e.g., aprocessing resource located external from a memory array, such as on aseparate integrated circuit chip). For instance, a number of embodimentscan provide for performing fully complete compute functions such asinteger add, subtract, multiply, divide, and CAM (content addressablememory) functions without transferring data out of the memory array andsensing circuitry via a bus (e.g., data bus, address bus, control bus),for instance. Such compute functions can involve performing a number oflogical operations (e.g., logical functions such as AND, OR, NOT, NOR,NAND, XOR, etc.). However, embodiments are not limited to theseexamples. For instance, performing logical operations can includeperforming a number of non-Boolean logic operations such as copy,compare, destroy, etc.

In previous approaches, data may be transferred from the array andsensing circuitry (e.g., via a bus comprising input/output (I/O) lines)to a processing resource such as a processor, microprocessor, and/orcompute engine, which may comprise ALU circuitry and/or other functionalunit circuitry configured to perform the appropriate logical operations.However, transferring data from a memory array and sensing circuitry tosuch processing resource(s) can involve significant power consumption.Even if the processing resource is located on a same chip as the memoryarray, significant power can be consumed in moving data out of the arrayto the compute circuitry, which can involve performing a sense line(which may be referred to herein as a digit line or data line) addressaccess (e.g., firing of a column decode signal) in order to transferdata from sense lines onto I/O lines (e.g., local I/O lines), moving thedata to the array periphery, and providing the data to the computefunction.

Furthermore, the circuitry of the processing resource(s) (e.g., computeengine) may not conform to pitch rules associated with a memory array.For example, the cells of a memory array may have a 4F² or 6F² cellsize, where “F” is a feature size corresponding to the cells. As such,the devices (e.g., logic gates) associated with ALU circuitry ofprevious PIM systems may not be capable of being formed on pitch withthe memory cells, which can affect chip size and/or memory density, forexample. A number of embodiments of the present disclosure includesensing circuitry formed on pitch with an array of memory cells andcapable of performing compute functions such as gather and scatteroperations local to the array of memory cells.

FIGS. 1A and 1D are block diagrams of an apparatus in the form of acomputing system 100 including a memory device 120 in accordance with anumber of embodiments of the present disclosure. The host 110, logic112, cache memory 113 and cache controller have been discussed in detailabove. The memory device 120 shown in FIG. 1A can include a controller140, e.g., memory controller, a channel controller 143, a bank arbiter145, a high speed interface (HSI) 141, a memory array 130 having sensingcircuitry 150 and/or logic circuitry 170. Each of these as used hereinmight also be separately considered an “apparatus.”

FIGS. 1A and 1D show the system 100 includes a host 110 coupled (e.g.,connected) to the memory device 120, which includes a memory array 130.Host 110 can be a host system such as a personal laptop computer, adesktop computer, a digital camera, a smart phone, or a memory cardreader, among various other types of hosts. Host 110 can include asystem motherboard and/or backplane and can include a number ofprocessing resources (e.g., one or more processors, microprocessors, orsome other type of controlling circuitry). The system 100 can includeseparate integrated circuits or both the host 110 and the memory device120 can be on the same integrated circuit. The system 100 can be, forinstance, a server system and/or a high performance computing (HPC)system and/or a portion thereof. Although the examples shown in FIGS. 1Aand 1D illustrates a system having a Von Neumann architecture,embodiments of the present disclosure can be implemented in non-VonNeumann architectures, which may not include one or more components(e.g., CPU, ALU, etc.) often associated with a Von Neumann architecture.

The memory array 130 can be a DRAM array, SRAM array, STT RAM array,PCRAM array, TRAM array, RRAM array, NAND flash array, and/or NOR flasharray, for instance. The array 130 can comprise memory cells arranged inrows coupled by access lines (which may be referred to herein as wordlines or select lines) and columns coupled by sense lines, which may bereferred to herein as data lines or digit lines. Although a single array130 is shown in FIG. 1A, embodiments are not so limited. For instance,memory device 120 may include a number of arrays 130 (e.g., a number ofbanks of DRAM cells, NAND flash cells, etc.).

The memory device 120 includes address circuitry 142 to latch addresssignals provided over a data bus 156 (e.g., an I/O bus) through I/Ocircuitry 144. Status and/or exception information can be provided fromthe controller 140 on the memory device 120 to a channel controller 143,including an out-of-band bus 157, which in turn can be provided from thememory device 120 to the host 110. Address signals are received throughaddress circuitry 142 and decoded by a row decoder 146 and a columndecoder 152 to access the memory array 130. A number of designatedportions of the array 130 may be provided to receive and to storecompute enabled cache lines having subrow select metadata datastructures 163 and block select metadata data structures 162. Data canbe read from memory array 130 by sensing voltage and/or current changeson the data lines using sensing circuitry 150. The sensing circuitry 150can read and latch a page (e.g., row) of data from the memory array 130.The I/O circuitry 144 can be used for bi-directional data communicationwith host 110 over the data bus 156. The write circuitry 148 is used towrite data to the memory array 130.

Controller 140, e.g., memory controller, may decode signals provided bycontrol bus 154 from the host 110. These signals can include chip enablesignals, write enable signals, and address latch signals that are usedto control operations performed on the memory array 130, including dataread, data write, and data erase operations. In various embodiments, thecontroller 140 is responsible for executing instructions from the host110. The controller 140 can be a state machine, a sequencer, or someother type of controller. The controller 140 can control shifting data(e.g., right or left) in an array, e.g., memory array 130.

Examples of the sensing circuitry 150 are described further below. Forinstance, in a number of embodiments, the sensing circuitry 150 cancomprise a number of sense amplifiers and a number of computecomponents, which may serve as, and be referred to herein as, anaccumulator and can be used to perform logical operations (e.g., on dataassociated with complementary data lines).

In a number of embodiments, the sensing circuitry 150 can be used toperform logical operations using data stored in array 130 as inputs andstore the results of the logical operations back to the array 130without transferring data via a sense line address access (e.g., withoutfiring a column decode signal). As such, various compute functions canbe performed using, and within, sensing circuitry 150 rather than (or inassociation with) being performed by processing resources external tothe sensing circuitry (e.g., by a processor associated with host 110and/or other processing circuitry, such as ALU circuitry, located ondevice 120 (e.g., on controller 140 or elsewhere)).

In various previous approaches, data associated with an operand, forinstance, would be read from memory via sensing circuitry and providedto external ALU circuitry via I/O lines (e.g., via local I/O linesand/or global I/O lines). The external ALU circuitry could include anumber of registers and would perform compute functions using theoperands, and the result would be transferred back to the array via theI/O lines. In contrast, in a number of embodiments of the presentdisclosure, sensing circuitry 150 is configured to perform logicaloperations on data stored in memory array 130 and store the result backto the memory array 130 without enabling an I/O line (e.g., a local I/Oline) coupled to the sensing circuitry 150. The sensing circuitry 150can be formed on pitch with the memory cells of the array. Logiccircuitry 170 can be coupled to the sensing circuitry 150 and caninclude additional peripheral sense amplifiers, registers, cache and/ordata buffers to store, cache and/or buffer, results of operationsdescribed herein.

As such, in a number of embodiments, circuitry external to array 130 andsensing circuitry 150 is not needed to perform compute functions as thesensing circuitry 150 can perform the appropriate logical operations toperform such compute functions without the use of an external processingresource. Therefore, the sensing circuitry 150 may be used to complimentand/or to replace, at least to some extent, such an external processingresource (or at least the bandwidth consumption of such an externalprocessing resource). In effect, the array 130 and sensing circuitry canfunction according to embodiments as a compute enabled cache upon thecontroller 140 receiving and operating on a cache line 160 having blockselect 162 and subrow select 163 metadata structures.

However, in a number of embodiments, the sensing circuitry 150 may beused to perform logical operations (e.g., to execute instructions) inaddition to logical operations performed by an external processingresource (e.g., host 110). For instance, host 110 and/or sensingcircuitry 150 may be limited to performing only certain logicaloperations and/or a certain number of logical operations.

Enabling an I/O line can include enabling (e.g., turning on) atransistor having a gate coupled to a decode signal (e.g., a columndecode signal) and a source/drain coupled to the I/O line. However,embodiments are not limited to not enabling an I/O line. For instance,in a number of embodiments, the sensing circuitry (e.g., 150) can beused to perform logical operations without enabling column decode linesof the array; however, the local I/O line(s) may be enabled in order totransfer a result to a suitable location other than back to the array130 (e.g., to an external register).

FIG. 1D is a block diagram of another apparatus architecture in the formof a computing system 100 including a plurality of memory devices 120-1,. . . , 120-N coupled to a host 110 via a channel controller 143 inaccordance with a number of embodiments of the present disclosure. In atleast one embodiment the channel controller 143 may be coupled to theplurality of memory devices 120-1, . . . , 120-N in an integrated mannerin the form of a module 118, e.g., formed on same chip with theplurality of memory devices 120-1, . . . , 120-N. In an alternativeembodiment, the channel controller 143 may be integrated with the host110, as illustrated by dashed lines 111, e.g., formed on a separate chipfrom the plurality of memory devices 120-1, . . . , 120-N. The channelcontroller 143 can be coupled to each of the plurality of memory devices120-1, . . . , 120-N via a control bus 154 as described in FIG. 1A whichin turn can be coupled to the host 110. The channel controller 143 canalso be coupled to each of the plurality of memory devices, 120-1, . . ., 120-N via a data bus 156 as described in FIG. 1A which in turn can becoupled to the host 110. In addition, the channel controller 143 can becoupled to each of the plurality of memory devices 120-1, . . . , 120-Nvia an out-of-bound (OOB) bus 157 associated with a high speed interface(HSI) 141 that is configured to report status, exception and other datainformation to the channel controller 143 to exchange with the host 110.

As shown in FIG. 1D, the channel controller 143 can receive the statusand exception information from a high speed interface (HSI) (alsoreferred to herein as a status channel interface) 141 associated with abank arbiter 145 in each of the plurality of memory devices 120-1, . . ., 120-N. In the example of FIG. 1B, each of the plurality of memorydevices 120-1, . . . , 120-N can include a bank arbiter 145 to sequencecontrol and data with a plurality of banks, e.g., Bank zero (0), Bankone (1), . . . , Bank six (6), Bank seven (7), etc. Each of theplurality of banks, Bank 0, . . . , Bank 7, can include a controller 140and other components, including an array of memory cells 130 and sensingcircuitry 150, logic circuitry 170, etc., as described in connectionwith FIG. 1A.

For example, each of the plurality of banks, e.g., Bank 0, . . . , Bank7, in the plurality of memory devices 120-1, . . . , 120-N can includeaddress circuitry 142 to latch address signals for data provided over adata bus 156 (e.g., an I/O bus) through I/O circuitry 144. Status and/orexception information can be provided from the controller 140 on thememory device 120 to the channel controller 143, using the OOB bus 157,which in turn can be provided from the plurality of memory devices120-1, . . . , 120-N to the host 110. For each of the plurality ofbanks, e.g., Bank 0, . . . , Bank 7, address signals can be receivedthrough address circuitry 142 and decoded by a row decoder 146 and acolumn decoder 152 to access the memory array 130. Data can be read frommemory array 130 by sensing voltage and/or current changes on the datalines using sensing circuitry 150. The sensing circuitry 150 can readand latch a page (e.g., row) of data from the memory array 130. The I/Ocircuitry 144 can be used for bi-directional data communication withhost 110 over the data bus 156. The write circuitry 148 is used to writedata to the memory array 130 and the OOB bus 157 can be used to reportstatus, exception and other data information to the channel controller143.

The channel controller 143 can include one or more local buffers tostore an program instructions and can include logic 160 to allocate aplurality of locations, e.g., subarrays or portions of subarrays, in thearrays of each respective bank to store bank commands, and arguments,(PIM commands) for the various banks associated with to operation ofeach of the plurality of memory devices 120-1, . . . , 120-N. Thechannel controller 143 can dispatch commands, e.g., PIM commands, to theplurality of memory devices 120-1, . . . , 120-N to store those programinstructions within a given bank of a memory device.

As described above in connection with FIG. 1A, the memory array 130 canbe a DRAM array, SRAM array, STT RAM array, PCRAM array, TRAM array,RRAM array, NAND flash array, and/or NOR flash array, for instance. Thearray 130 can comprise memory cells arranged in rows coupled by accesslines (which may be referred to herein as word lines or select lines)and columns coupled by sense lines, which may be referred to herein asdata lines or digit lines.

As in FIG. 1A, a controller 140, e.g., bank control logic and/orsequencer, associated with any particular bank, Bank 0, . . . , Bank 7,in a given memory device, 120-1, . . . , 120-N, can decode signalsprovided by control bus 154 from the host 110. These signals can includechip enable signals, write enable signals, and address latch signalsthat are used to control operations performed on the memory array 130,including data read, data write, and data erase operations. In variousembodiments, the controller 140 is responsible for executinginstructions from the host 110. And, as above, the controller 140 can bea state machine, a sequencer, or some other type of controller. Forexample, the controller 140 can control shifting data (e.g., right orleft) in an array, e.g., memory array 130.

FIG. 1E is a block diagram of a bank 121-1 to a memory device inaccordance with a number of embodiments of the present disclosure. Thatis bank 121-1 can represent an example bank to a memory device such asBank 0, . . . , Bank 7 (121-0, . . . , 121-7) shown in FIG. 1B. Asdescribed in FIG. 1B, a bank architecture can include a plurality ofmain memory columns (shown horizontally as X), e.g., 16,384 columns inan example DRAM bank. Additionally, the bank 121-1 may be divided upinto sections, 123-1, 123-2, . . . , 123-N, separated by amplificationregions for a data path. Each of the bank sections 123-1, . . . , 123-Ncan include a plurality of rows (shown vertically as Y), e.g., eachsection may include 16,384 rows in an example DRAM bank. One or more ofthe bank sections 123-1, . . . , 123-N may include a number of locationsconfigured to receive and store compute enabled cache blocks, e.g.,127-0, . . . , 127-N as shown in FIG. 1B, having subrow select and blockselect metadata data structures. Example embodiments are not limited tothe example horizontal and/or vertical orientation of columns and rowsdescribed here or the example numbers thereof.

As shown in FIG. 1E, the bank architecture can include logic circuitry170, such as sense amplifiers, registers, cache and data buffering, thatis coupled to the bank sections 123-1, . . . , 123-N. The logiccircuitry 170 can provide another form of cache such as logic circuitry170 associated with the sensing circuitry 150 and array 130 as shown inFIG. 1A. Further, as shown in FIG. 1E, the bank architecture can beassociated with bank control, e.g., controller, 140. The bank controlshown in FIG. 1E can, in example, represent at least a portion of thefunctionality embodied by and contained in the controller 140 shown inFIGS. 1A and 1D.

FIG. 1F is another block diagram of a bank 121 to a memory device inaccordance with a number of embodiments of the present disclosure. Forexample, bank 121 can represent an example bank to a memory device suchas Bank 0, . . . , Bank 7 (121-0, . . . , 121-7) shown in FIG. 1D. Asshown in FIG. 1F, a bank architecture can include a control bus 154coupled controller 140. Again, the controller 140 shown in FIG. 1F can,for example, represent at least a portion of the functionality embodiedby and contained in the controller 140 shown in FIGS. 1A and 1D. Also,as shown in FIG. 1F, the bank architecture can include a data bus 156coupled to a plurality of control/data registers in an instruction,e.g., program instructions (PIM commands), read path 151 and coupled toa plurality of bank sections, e.g., bank section 123, in a particularbank 121.

As shown in FIG. 1F, a bank section 123 can be further subdivided into aplurality of sub-arrays (or subarrays) 125-1, 125-2, . . . , 125-N againseparated by of plurality of sensing circuitry and logic 150/170 asshown in FIG. 1A and described further in connection with FIGS. 2-4. Inone example, a bank section 121 may be divided into sixteen (16)subarrays. However, embodiments are not limited to this example number.One or more of the sub-arrays 125-1, 125-2, . . . , 125-N may include anumber of locations configured to receive and store compute enabledcache blocks, e.g., 127-0, . . . , 127-N as shown in FIG. 1B, havingsubrow select and block select metadata data structures.

FIG. 1F, illustrates a controller 140 coupled to a write path 149 andcoupled to each of the subarrays 125-1, . . . , 125-N in the bank 123.Alternatively or additionally, logic circuitry 170 shown in FIG. 1A maybe used as an instruction cache, e.g., used to cache and/or re-cacheretrieved instructions local (“on-pitch”) to a particular bank. In atleast one embodiment, the plurality of subarrays 125-1, . . . , 125-N,and/or portions of the plurality of subarrays, may be referred to as aplurality of locations for storing program instructions, e.g., PIMcommands, and/or constant data to a bank 123 in a memory device.

According to embodiments of the present disclosure, the controller 140is configured to receive a block of instructions, compute enabled cacheblocks, e.g., 127-0, . . . , 127-N as shown in FIG. 1B having subrowselect and block select metadata data structures, and/or constant datafrom a host, e.g., host 110 in FIG. 1A. Alternatively, the block ofinstructions, compute enabled cache blocks, e.g., 127-0, . . . , 127-Nas shown in FIG. 1B having subrow select and block select metadata datastructures, and/or constant data may be received to the controller 140from a channel controller 143 either integrated with the host 110 orseparate from the host, e.g., integrated in the form of a module 118with a plurality of memory devices, 120-1, . . . , 120-N, as shown inFIG. 1D.

The block of instructions and/or data can include a set of programinstructions, e.g. PIM commands, and/or constant data, e.g., data to setup for PIM calculations. According to embodiments, the controller 140 isconfigured to store the block of instructions and/or constant data fromthe host 110 and/or channel controller 143 in an array, e.g., array 130shown in FIG. 1A and/or 123 shown in FIG. 1D, of a bank, e.g., banks121-0, . . . , 121-7, shown in FIGS. 1D, 1E and 1F. The controller 140is further configured, e.g. includes logic in the form of hardwarecircuitry and/or application specific integrated circuitry (ASIC), toroute the program instructions to the sensing circuitry, including acompute component, such as sensing circuitry shown as 150 in FIG. 1A andcompute components 231 and 331 in FIGS. 2 and 3, to perform logicalfunctions and/or operations, e.g., program instruction execution, asdescribed herein.

In at least one embodiment the controller 140 is configured to use DRAMprotocol and DRAM logical and electrical interfaces to receive theprogram instructions and/or constant data from the host 110 and/orchannel controller 143 and to route the program instructions and/orconstant data to a compute component of sensing circuitry 150, 250and/or 350. The program instructions and/or constant data received tothe controller 140 can be pre-resolved, e.g., pre-defined, by aprogrammer and/or provided to the host 110 and/or channel controller143.

In some embodiments, as seen in FIG. 1D, the array of memory cells (130in FIG. 1A) includes a plurality of banks of memory cells 120-1, . . . ,120-N and the memory device 120 includes a bank arbiter 145 coupled toeach of the plurality of banks 120-1, . . . , 120-N. In suchembodiments, each bank arbiter is configured to receive an instructionblock of program instructions, compute enabled cache blocks havingsubrow select and block select metadata data structures, and/or constantdata relevant to a particular bank from the bank arbiter 145. Thecontroller 140 can then store instructions in the received instructionblock, compute enabled cache blocks, and/or constant data to a pluralityof locations for the particular bank as allocated by the host 110 and/orchannel controller 143. For example, the host 110 and/or channelcontroller 143 is configured to address translate the plurality oflocations for the bank arbiter 145 to assign to banks of the memorydevice 120. In at least one embodiment, as shown in FIG. 1D, theplurality of locations includes a number of subarrays 125-1, . . . ,125-N in the DRAM banks 121-1, . . . , 121-7 and/or portions of thenumber of subarrays.

According to embodiments, each controller 140 can be configured toreceive compute enabled cache lines 160 from the host 110 and/or channelcontroller 143, e.g., on data bus 156, to store cache blocks received toa given bank, 121-1, . . . , 121-7. The controller 140 is configured tothen retrieve cache block data on data bus 156 with control and dataregisters 151, from the plurality of locations for the particular bankand execute logical operations using the compute component of thesensing circuitry 150. The controller 140 can cache retrieved cacheblocks local to the particular bank, e.g. array 130, bank sections 123and/or subarray 125, to handle branches, loops, logical and dataoperations contained within the instructions block execution. And, thecontroller 140 can re-cache retrieved instructions as needed. Thus, thesize of the dedicated instruction memory (cache) on the DRAM part doesnot have to be increased for a PIM system.

In some embodiments, a plurality of memory devices 120-1, . . . , 120-Nare coupled to a host 110 and/or channel controller 143. Here, the host110 and/or channel controller 143 can dispatch cache blocks to anappropriate bank arbiter 145-1, . . . , 145-N for the plurality ofmemory devices, 120-1, . . . , 120-N, e.g., over a data bus 156.

Further, according to embodiments, the controller 140 is configured suchthat a bank 121 can receive a subsequent cache line 160 associated withanother cache block relevant to the particular bank and use the blockselect 162 and subrow select 163 metadata data structures in thereceived cache lines 160 to store and access cache blocks to/from aplurality of locations for the particular bank while, e.g., in parallel,the controller 140 is operating on another previously retrieved cacheblock. Hence, the embodiments described herein avoid needing to wait forfuture, or a next set of cache block access instructions, e.g., PIMcommands, to be received from a host 110 and/or channel controller 143.Instead, the apparatus and methods devices described herein facilitatethe memory device 120 functioning as a last layer cache (LLC) in a DRAMpart for cache blocks and can facilitate a compute enabled cachedirectly on-chip, on-pitch with the memory device 120 in the PIM system,e.g., PIMRAM.

As the reader will appreciate, and as described in more detail in theexamples of FIGS. 2-4, the controller 140 is configure to control theexecution of program instructions, e.g., PIM commands, by controllingthe sensing circuitry 150, including compute components 251 and/or 35 1,to implement logical functions such as AND, OR, NOT, NAND, NOR, and XORlogical functions. Additionally the controller 140 is configured tocontrol the sensing circuitry 150 to perform non-Boolean logicoperations, including copy, compare and erase operations, as part ofexecuting program instructions, e.g., PIM commands.

FIG. 2 is a schematic diagram illustrating sensing circuitry 250 inaccordance with a number of embodiments of the present disclosure. Thesensing circuitry 250 can correspond to sensing circuitry 150 shown inFIGS. 1A and 1B. The sense amplifier 206 of sensing circuitry 250 cancorrespond to sense amplifiers 206 shown in FIG. 2, and the computecomponent 231 of sensing circuitry 250 can correspond to sensingcircuitry, including compute component, 150 shown in FIG. 1A, forexample.

A memory cell comprises a storage element (e.g., capacitor) and anaccess device (e.g., transistor). For instance, a first memory cellcomprises transistor 202-1 and capacitor 203-1, and a second memory cellcomprises transistor 202-2 and capacitor 203-2, etc. In this example,the memory array 230 is a DRAM array of 1T1C (one transistor onecapacitor) memory cells. In a number of embodiments, the memory cellsmay be destructive read memory cells (e.g., reading the data stored inthe cell destroys the data such that the data originally stored in thecell is refreshed after being read).

The cells of the memory array 230 can be arranged in rows coupled byword lines 204-X (Row X), 204-Y (Row Y), etc., and columns coupled bypairs of complementary sense lines (e.g., data linesDIGIT(n−1)/DIGIT(n−1), DIGIT(n)/DIGIT(n)_, DIGIT(n+1)/DIGIT(n+1)_). Theindividual sense lines corresponding to each pair of complementary senselines can also be referred to as data lines 205-1 (D) and 205-2 (D_)respectively. Although only one pair of complementary data lines areshown in FIG. 2, embodiments of the present disclosure are not solimited, and an array of memory cells can include additional columns ofmemory cells and/or data lines (e.g., 4,096, 8,192, 16,384, etc.).

Memory cells can be coupled to different data lines and/or word lines.For example, a first source/drain region of a transistor 202-1 can becoupled to data line 205-1 (D), a second source/drain region oftransistor 202-1 can be coupled to capacitor 203-1, and a gate of atransistor 202-1 can be coupled to word line 204-X. A first source/drainregion of a transistor 202-2 can be coupled to data line 205-2 (D_), asecond source/drain region of transistor 202-2 can be coupled tocapacitor 203-2, and a gate of a transistor 202-2 can be coupled to wordline 204-Y. The cell plate, as shown in FIG. 2, can be coupled to eachof capacitors 203-1 and 203-2. The cell plate can be a common node towhich a reference voltage (e.g., ground) can be applied in variousmemory array configurations.

The memory array 230 is coupled to sensing circuitry 250 in accordancewith a number of embodiments of the present disclosure. In this example,the sensing circuitry 250 comprises a sense amplifier 206 and a computecomponent 231 corresponding to respective columns of memory cells (e.g.,coupled to respective pairs of complementary data lines). The senseamplifier 206 can be coupled to the pair of complementary sense lines205-1 and 205-2. The compute component 231 can be coupled to the senseamplifier 206 via pass gates 207-1 and 207-2. The gates of the passgates 207-1 and 207-2 can be coupled to logical operation selectionlogic 213.

The logical operation selection logic 213 can be configured to includepass gate logic for controlling pass gates that couple the pair ofcomplementary sense lines un-transposed between the sense amplifier 206and the compute component 231 (as shown in FIG. 2) and/or swap gatelogic for controlling swap gates that couple the pair of complementarysense lines transposed between the sense amplifier 206 and the computecomponent 231. The logical operation selection logic 213 can also becoupled to the pair of complementary sense lines 205-1 and 205-2. Thelogical operation selection logic 213 can be configured to controlcontinuity of pass gates 207-1 and 207-2 based on a selected logicaloperation, as described in detail below for various configurations ofthe logical operation selection logic 413.

The sense amplifier 206 can be operated to determine a data value (e.g.,logic state) stored in a selected memory cell. The sense amplifier 206can comprise a cross coupled latch, which can be referred to herein as aprimary latch. In the example illustrated in FIG. 2, the circuitrycorresponding to sense amplifier 206 comprises a latch 215 includingfour transistors coupled to a pair of complementary data lines D 205-1and D_205-2. However, embodiments are not limited to this example. Thelatch 215 can be a cross coupled latch (e.g., gates of a pair oftransistors, such as n-channel transistors (e.g., NMOS transistors)227-1 and 227-2 are cross coupled with the gates of another pair oftransistors, such as p-channel transistors (e.g., PMOS transistors)229-1 and 229-2). The cross coupled latch 215 comprising transistors227-1, 227-2, 229-1, and 229-2 can be referred to as a primary latch.

In operation, when a memory cell is being sensed (e.g., read), thevoltage on one of the data lines 205-1 (D) or 205-2 (D_) will beslightly greater than the voltage on the other one of data lines 205-1(D) or 205-2 (D_). An ACT signal and the RNL* signal can be driven lowto enable (e.g., fire) the sense amplifier 206. The data lines 205-1 (D)or 205-2 (D_) having the lower voltage will turn on one of the PMOStransistor 229-1 or 229-2 to a greater extent than the other of PMOStransistor 229-1 or 229-2, thereby driving high the data line 205-1 (D)or 205-2 (D_) having the higher voltage to a greater extent than theother data line 205-1 (D) or 205-2 (D_) is driven high.

Similarly, the data line 205-1 (D) or 205-2 (D_) having the highervoltage will turn on one of the NMOS transistor 227-1 or 227-2 to agreater extent than the other of the NMOS transistor 227-1 or 227-2,thereby driving low the data line 205-1 (D) or 205-2 (D_) having thelower voltage to a greater extent than the other data line 205-1 (D) or205-2 (D_) is driven low. As a result, after a short delay, the dataline 205-1 (D) or 205-2 (D_) having the slightly greater voltage isdriven to the voltage of the supply voltage V_(CC) through sourcetransistor 211, and the other data line 205-1 (D) or 205-2 (D_) isdriven to the voltage of the reference voltage (e.g., ground) throughthe sink transistor 213. Therefore, the cross coupled NMOS transistors227-1 and 227-2 and PMOS transistors 229-1 and 229-2 serve as a senseamplifier pair, which amplify the differential voltage on the data lines205-1 (D) and 205-2 (D_) and operate to latch a data value sensed fromthe selected memory cell. As used herein, the cross coupled latch ofsense amplifier 206 may be referred to as a primary latch 215.

Embodiments are not limited to the sense amplifier 206 configurationillustrated in FIG. 2. As an example, the sense amplifier 206 can becurrent-mode sense amplifier and/or single-ended sense amplifier (e.g.,sense amplifier coupled to one data line). Also, embodiments of thepresent disclosure are not limited to a folded data line architecturesuch as that shown in FIG. 2.

The sense amplifier 206 can, in conjunction with the compute component231, be operated to perform various logical operations using data froman array as input. In a number of embodiments, the result of a logicaloperation can be stored back to the array without transferring the datavia a data line address access (e.g., without firing a column decodesignal such that data is transferred to circuitry external from thearray and sensing circuitry via local I/O lines). As such, a number ofembodiments of the present disclosure can enable performing logicaloperations and compute functions associated therewith using less powerthan various previous approaches. Additionally, since a number ofembodiments eliminate the need to transfer data across I/O lines inorder to perform compute functions (e.g., between memory and discreteprocessor), a number of embodiments can enable an increased parallelprocessing capability as compared to previous approaches.

The sense amplifier 206 can further include equilibration circuitry 214,which can be configured to equilibrate the data lines 205-1 (D) and205-2 (D_). In this example, the equilibration circuitry 214 comprises atransistor 224 coupled between data lines 205-1 (D) and 205-2 (D_). Theequilibration circuitry 214 also comprises transistors 225-1 and 225-2each having a first source/drain region coupled to an equilibrationvoltage (e.g., V_(DD)/2), where V_(DD) is a supply voltage associatedwith the array. A second source/drain region of transistor 225-1 can becoupled data line 205-1 (D), and a second source/drain region oftransistor 225-2 can be coupled data line 205-2 (D_). Gates oftransistors 224, 225-1, and 225-2 can be coupled together, and to anequilibration (EQ) control signal line 226. As such, activating EQenables the transistors 224, 225-1, and 225-2, which effectively shortsdata lines 205-1 (D) and 205-2 (D_) together and to the an equilibrationvoltage (e.g., V_(cc)/2).

Although FIG. 2 shows sense amplifier 206 comprising the equilibrationcircuitry 214, embodiments are not so limited, and the equilibrationcircuitry 214 may be implemented discretely from the sense amplifier206, implemented in a different configuration than that shown in FIG. 2,or not implemented at all.

As described further below, in a number of embodiments, the sensingcircuitry (e.g., sense amplifier 206 and compute component 231) can beoperated to perform a selected logical operation and initially store theresult in one of the sense amplifier 206 or the compute component 231without transferring data from the sensing circuitry via an I/O line(e.g., without performing a data line address access via activation of acolumn decode signal, for instance).

Performance of logical operations (e.g., Boolean logical functionsinvolving data values) is fundamental and commonly used. Boolean logicfunctions are used in many higher level functions. Consequently, speedand/or power efficiencies that can be realized with improved logicaloperations, can translate into speed and/or power efficiencies of higherorder functionalities.

As shown in FIG. 2, the compute component 231 can also comprise a latch,which can be referred to herein as a secondary latch 264. The secondarylatch 264 can be configured and operated in a manner similar to thatdescribed above with respect to the primary latch 215, with theexception that the pair of cross coupled p-channel transistors (e.g.,PMOS transistors) comprising the secondary latch can have theirrespective sources coupled to a supply voltage (e.g., V_(DD)), and thepair of cross coupled n-channel transistors (e.g., NMOS transistors) ofthe secondary latch can have their respective sources selectivelycoupled to a reference voltage (e.g., ground), such that the secondarylatch is continuously enabled. The configuration of the computecomponent is not limited to that shown in FIG. 2 at 231, and variousother embodiments are described further below.

FIG. 3 is a schematic diagram illustrating sensing circuitry capable ofimplementing an XOR logical operation in accordance with a number ofembodiments of the present disclosure. FIG. 3 shows a sense amplifier306 coupled to a pair of complementary sense lines 305-1 and 305-2, anda compute component 331 coupled to the sense amplifier 306 via passgates 307-1 and 307-2. The sense amplifier 306 shown in FIG. 3 cancorrespond to sense amplifier 206 shown in FIG. 2. The compute component331 shown in FIG. 3 can correspond to sensing circuitry, includingcompute component, 150 shown in FIG. 1A, for example. The logicaloperation selection logic 313 shown in FIG. 3 can correspond to logicaloperation selection logic 413 shown in FIG. 4, for example.

The gates of the pass gates 307-1 and 307-2 can be controlled by alogical operation selection logic signal, Pass. For example, an outputof the logical operation selection logic can be coupled to the gates ofthe pass gates 307-1 and 307-2. The compute component 331 can comprise aloadable shift register configured to shift data values left and right.

According to the embodiment illustrated in FIG. 3, the computecomponents 331 can comprise respective stages (e.g., shift cells) of aloadable shift register configured to shift data values left and right.For example, as illustrated in FIG. 3, each compute component 331 (e.g.,stage) of the shift register comprises a pair of right-shift transistors381 and 386, a pair of left-shift transistors 389 and 390, and a pair ofinverters 387 and 388. The signals PHASE 1 R, PHASE 2 R, PHASE 1 L, andPHASE 2 L can be applied to respective control lines 382, 383, 391 and392 to enable/disable feedback on the latches of the correspondingcompute components 331 in association with performing logical operationsand/or shifting data in accordance with embodiments described herein.

The sensing circuitry shown in FIG. 3 also shows a logical operationselection logic 313 coupled to a number of logic selection control inputcontrol lines, including ISO, TF, TT, FT, and FF. Selection of a logicaloperation from a plurality of logical operations is determined from thecondition of logic selection control signals on the logic selectioncontrol input control lines, as well as the data values present on thepair of complementary sense lines 305-1 and 305-2 when the isolationtransistors are enabled via the ISO control signal being asserted.

According to various embodiments, the logical operation selection logic313 can include four logic selection transistors: logic selectiontransistor 362 coupled between the gates of the swap transistors 342 anda TF signal control line, logic selection transistor 352 coupled betweenthe gates of the pass gates 307-1 and 307-2 and a TT signal controlline, logic selection transistor 354 coupled between the gates of thepass gates 307-1 and 307-2 and a FT signal control line, and logicselection transistor 364 coupled between the gates of the swaptransistors 342 and a FF signal control line. Gates of logic selectiontransistors 362 and 352 are coupled to the true sense line throughisolation transistor 350-1 (having a gate coupled to an ISO signalcontrol line). Gates of logic selection transistors 364 and 354 arecoupled to the complementary sense line through isolation transistor350-2 (also having a gate coupled to an ISO signal control line).

Data values present on the pair of complementary sense lines 305-1 and305-2 can be loaded into the compute component 331 via the pass gates307-1 and 307-2. The compute component 331 can comprise a loadable shiftregister. When the pass gates 307-1 and 307-2 are OPEN, data values onthe pair of complementary sense lines 305-1 and 305-2 are passed to thecompute component 331 and thereby loaded into the loadable shiftregister. The data values on the pair of complementary sense lines 305-1and 305-2 can be the data value stored in the sense amplifier 306 whenthe sense amplifier is fired. The logical operation selection logicsignal, Pass, is high to OPEN the pass gates 307-1 and 307-2.

The ISO, TF, TT, FT, and FF control signals can operate to select alogical function to implement based on the data value (“B”) in the senseamplifier 306 and the data value (“A”) in the compute component 331. Inparticular, the ISO, TF, TT, FT, and FF control signals are configuredto select the logical function to implement independent from the datavalue present on the pair of complementary sense lines 305-1 and 305-2(although the result of the implemented logical operation can bedependent on the data value present on the pair of complementary senselines 305-1 and 305-2. For example, the ISO, TF, TT, FT, and FF controlsignals select the logical operation to implement directly since thedata value present on the pair of complementary sense lines 305-1 and305-2 is not passed through logic to operate the gates of the pass gates307-1 and 307-2.

Additionally, FIG. 3 shows swap transistors 342 configured to swap theorientation of the pair of complementary sense lines 305-1 and 305-2between the sense amplifier 313-7 and the compute component 331. Whenthe swap transistors 342 are OPEN, data values on the pair ofcomplementary sense lines 305-1 and 305-2 on the sense amplifier 306side of the swap transistors 342 are oppositely-coupled to the pair ofcomplementary sense lines 305-1 and 305-2 on the compute component 331side of the swap transistors 342, and thereby loaded into the loadableshift register of the compute component 331.

The logical operation selection logic signal Pass can be activated(e.g., high) to OPEN the pass gates 307-1 and 307-2 (e.g., conducting)when the ISO control signal line is activated and either the TT controlsignal is activated (e.g., high) with data value on the true sense lineis “1” or the FT control signal is activated (e.g., high) with the datavalue on the complement sense line is “1.”

The data value on the true sense line being a “1” OPENs logic selectiontransistors 352 and 362. The data value on the complimentary sense linebeing a “1” OPENs logic selection transistors 354 and 364. If the ISOcontrol signal or either the respective TT/FT control signal or the datavalue on the corresponding sense line (e.g., sense line to which thegate of the particular logic selection transistor is coupled) is nothigh, then the pass gates 307-1 and 307-2 will not be OPENed by aparticular logic selection transistor.

The logical operation selection logic signal PassF can be activated(e.g., high) to OPEN the swap transistors 342 (e.g., conducting) whenthe ISO control signal line is activated and either the TF controlsignal is activated (e.g., high) with data value on the true sense lineis “1,” or the FF control signal is activated (e.g., high) with the datavalue on the complement sense line is “1.” If either the respectivecontrol signal or the data value on the corresponding sense line (e.g.,sense line to which the gate of the particular logic selectiontransistor is coupled) is not high, then the swap transistors 342 willnot be OPENed by a particular logic selection transistor.

The Pass* control signal is not necessarily complementary to the Passcontrol signal. It is possible for the Pass and Pass* control signals toboth be activated or both be deactivated at the same time. However,activation of both the Pass and Pass* control signals at the same timeshorts the pair of complementary sense lines together, which may be adisruptive configuration to be avoided.

The sensing circuitry illustrated in FIG. 3 is configured to select oneof a plurality of logical operations to implement directly from the fourlogic selection control signals (e.g., logical operation selection isnot dependent on the data value present on the pair of complementarysense lines). Some combinations of the logic selection control signalscan cause both the pass gates 307-1 and 307-2 and swap transistors 342to be OPEN at the same time, which shorts the pair of complementarysense lines 305-1 and 305-2 together. According to a number ofembodiments of the present disclosure, the logical operations which canbe implemented by the sensing circuitry illustrated in FIG. 3 can be thelogical operations summarized in the logic tables shown in FIG. 4.

FIG. 4 is a logic table illustrating selectable logic operation resultsimplemented by a sensing circuitry shown in FIG. 3 in accordance with anumber of embodiments of the present disclosure. The four logicselection control signals (e.g., TF, TT, FT, and FF), in conjunctionwith a particular data value present on the complementary sense lines,can be used to select one of plural logical operations to implementinvolving the starting data values stored in the sense amplifier 306 andcompute component 331. The four control signals, in conjunction with aparticular data value present on the complementary sense lines, controlsthe continuity of the pass gates 307-1 and 307-2 and swap transistors342, which in turn affects the data value in the compute component 331and/or sense amplifier 306 before/after firing. The capability toselectably control continuity of the swap transistors 342 facilitatesimplementing logical operations involving inverse data values (e.g.,inverse operands and/or inverse result), among others.

Logic Table 4-1 illustrated in FIG. 4 shows the starting data valuestored in the compute component 331 shown in column A at 444, and thestarting data value stored in the sense amplifier 306 shown in column Bat 445. The other 3 column headings in Logic Table 4-1 refer to thecontinuity of the pass gates 307-1 and 307-2, and the swap transistors342, which can respectively be controlled to be OPEN or CLOSED dependingon the state of the four logic selection control signals (e.g., TF, TT,FT, and FF), in conjunction with a particular data value present on thepair of complementary sense lines 305-1 and 305-2. The “Not Open” columncorresponds to the pass gates 307-1 and 307-2 and the swap transistors342 both being in a non-conducting condition, the “Open True”corresponds to the pass gates 307-1 and 307-2 being in a conductingcondition, and the “Open Invert” corresponds to the swap transistors 342being in a conducting condition. The configuration corresponding to thepass gates 307-1 and 307-2 and the swap transistors 342 both being in aconducting condition is not reflected in Logic Table 4-1 since thisresults in the sense lines being shorted together.

Via selective control of the continuity of the pass gates 307-1 and307-2 and the swap transistors 342, each of the three columns of theupper portion of Logic Table 4-1 can be combined with each of the threecolumns of the lower portion of Logic Table 4-1 to provide 3×3=9different result combinations, corresponding to nine different logicaloperations, as indicated by the various connecting paths shown at 475.The nine different selectable logical operations that can be implementedby the sensing circuitry (e.g., 150 in FIG. 1A) are summarized in LogicTable 4-2 illustrated in FIG. 4, including an XOR logical operation.

The columns of Logic Table 4-2 illustrated in FIG. 4 show a heading 480that includes the state of logic selection control signals. For example,the state of a first logic selection control signal is provided in row476, the state of a second logic selection control signal is provided inrow 477, the state of a third logic selection control signal is providedin row 478, and the state of a fourth logic selection control signal isprovided in row 479. The particular logical operation corresponding tothe results is summarized in row 447.

While example embodiments including various combinations andconfigurations of sensing circuitry, sense amplifiers, computecomponent, dynamic latches, isolation devices, and/or shift circuitryhave been illustrated and described herein, embodiments of the presentdisclosure are not limited to those combinations explicitly recitedherein. Other combinations and configurations of the sensing circuitry,sense amplifiers, compute component, dynamic latches, isolation devices,and/or shift circuitry disclosed herein are expressly included withinthe scope of this disclosure.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anarrangement calculated to achieve the same results can be substitutedfor the specific embodiments shown. This disclosure is intended to coveradaptations or variations of one or more embodiments of the presentdisclosure. It is to be understood that the above description has beenmade in an illustrative fashion, and not a restrictive one. Combinationof the above embodiments, and other embodiments not specificallydescribed herein will be apparent to those of skill in the art uponreviewing the above description. The scope of the one or moreembodiments of the present disclosure includes other applications inwhich the above structures and methods are used. Therefore, the scope ofone or more embodiments of the present disclosure should be determinedwith reference to the appended claims, along with the full range ofequivalents to which such claims are entitled.

In the foregoing Detailed Description, some features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the disclosed embodiments of the presentdisclosure have to use more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thus,the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment.

What is claimed is:
 1. An apparatus, comprising: a memory devicecomprising a memory array and sensing circuitry comprising a pluralityof sense amplifiers and a plurality of compute components to performlogical operations; a host coupled to the memory device and comprising acache controller, the cache controller configured to: create a blockselect as metadata to a cache line to control alignment of cache blockswithin the memory array; and create a subrow select as metadata to thecache line to control placement of the cache line on a particular row inthe memory array to align the cache line to one or more of the pluralityof sense amplifiers.
 2. The apparatus of claim 1, wherein the hostcomprises a processing resource coupled to a last layer cache (LLC) viathrough silicon vias (TSVs) and wherein the cache line is moved from theLLCs to the memory device.
 3. The apparatus of claim 2, wherein theblock select corresponds to a width of an interface coupling the host tothe memory device.
 4. The apparatus of claim 1, wherein the memorydevice is a last layer cache (LLC) memory.
 5. The apparatus of claim 4,wherein the plurality of sense amplifiers are configured to access andto operate on cached data in the LLC memory without moving the cacheddata to a higher level in the memory.
 6. The apparatus of claim 1,wherein a controller of the memory device is configured to: change theblock select and the subrow select; relocate the cached datatransparently to a host processor of the host; and wherein the blockselect and the subrow select are not part of an address space of thehost processor.
 7. The apparatus of claim 6, wherein the cachecontroller is configured to store a copy of the block select and thesubrow select with the host processor.
 8. The apparatus of claim 1,wherein the memory device is configured to: use the block select tocontrol alignment of cached data in the memory array; and use the subrowselect to control resource allocation in the memory array.
 9. Anapparatus, comprising: a host; a memory device coupled to the host,functioning a last layer cache (LLC) memory, and configured to: receivea cache line having block select and subrow select metadata from thehost processor; and operate on the block select and subrow selectmetadata to: control alignment of cache blocks in an array of the memorydevice; and allow the cache line to be placed on a particular row of thearray to align the cache line for processing in the LLC memory.
 10. Theapparatus of claim 9, wherein the host further includes a cachecontroller to: create the block select metadata and insert to the cacheline; and create the subrow select metadata and insert to the cacheline.
 11. The apparatus of claim 9, wherein the block select metadataand the row select metadata are stored internal to the memory device andare transparent to an address space of a processing resource of thehost.
 12. The apparatus of claim 9, wherein each cache line is handledas multiple vectors of different bit length values.
 13. The apparatus ofclaim 12, wherein each of the different bit length values of themultiple vectors is further subdivided into multiple elements.
 14. Theapparatus of claim 13, wherein a controller of the memory device isconfigured to use the subrow select metadata to select a subarray toplace an element of the multiple elements of a vector.
 15. The apparatusof claim 9, wherein the memory device is configured to: store the cacheblocks in the array; and retrieve a cache line to perform logicaloperations with a plurality of compute components and the plurality ofsense amplifiers of the memory device.
 16. A system for operating acache memory, comprising: a host processor; and a last layer cache (LLC)memory coupled to the host processor via through silicon vias (TSVs),and configured to: receive a cache line having block select and subrowselect metadata; and control placement, utilizing the block select andsubrow select metadata, of the cache line on a particular row in theLLC.
 17. The system of claim 16, wherein the LLC memory is a threedimensional (3D) integrated memory.
 18. The system of claim 16, whereinmemory banks of the LLC memory have independent TSV paths coupling thememory banks to the host processor.
 19. The system of claim 16, furthercomprising a cache controller configured to control the TSV paths. 20.The system of claim 16, wherein the host processor is further configuredto move the cache line having the block select and subrow selectmetadata from a static random access memory (SRAM) of the host processorto the LLC memory.